A benchmark test for room air distribution: the backward facing step flow

Peter V. Nielsen, Chen Zhang, Christina Thyssen Kjær, Daniel Henrique Leiria E. Pereira, Henriette Ljunggren Nørholm, Truls Ramstad, Anastasios Rovithakis, Rasmus Lund Jensen

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This paper concerns the use of Computational Fluid Dynamics (CFD) for the prediction of room air movement and provide a guide on selecting of the proper turbulence model. The benchmark which developed here for the first time is a backward-facing step flow problem. The measurements is performed in a small-scale model and the velocity filed is measured by Particle Image Velocimetry (PIV). The measurements focus on transitional flow and fully developed turbulent flow at isothermal condition. The PIV measurements and different CFD predictions are compared. The CFD predictions are generally slightly diverse, and this is, among other things, the result of using different turbulence models as well as using different software codes, grid distribution and boundary values etc. The k-ϵ family of turbulence models is an option for fully developed flow, and the k-ω family does work for transitional low turbulent flow in this backward-facing step flow.

Original languageEnglish
Article number032017
JournalIOP Conference Series: Materials Science and Engineering
Issue number3
Number of pages7
Publication statusPublished - 2019
EventConference on Indoor Air Quality, Ventilation and Energy Conservation in Buildings: Healthy Nearly Zero Energy Buildings - Politecnico di Bari, Bari, Italy
Duration: 5 Sep 20197 Sep 2019
Conference number: 10


ConferenceConference on Indoor Air Quality, Ventilation and Energy Conservation in Buildings
LocationPolitecnico di Bari
Internet address



  • CFD benchmark
  • Turbulence model
  • PIV

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